From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A09A7C07E95 for ; Mon, 19 Jul 2021 17:12:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D0C860FE9 for ; Mon, 19 Jul 2021 17:12:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351118AbhGSQbk (ORCPT ); Mon, 19 Jul 2021 12:31:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:56906 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347438AbhGSPQV (ORCPT ); Mon, 19 Jul 2021 11:16:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 23708611C1; Mon, 19 Jul 2021 15:56:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626710216; bh=4l/AoMsvGwjk7Lsth8aoRoQQpUwOUt4rTVkI0sOT9vM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hdEjEs94FYfIakBWR0n+tM4VlrHf6i7t/yBmd8CSfy9sjrBCjrxsDdqJ6pMRMx5VO 4NCyuQwql4Pw4FaR2/1O3fImwpYbV1PNBlBGV4iIgmJ8y6hf5I5q3IxC4o17w06wV4 Igwye1wqN2Yxj69fjCWDjGgJ/5ptT+hJPJpQgVOY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hulk Robot , Zou Wei , Guenter Roeck , Vladimir Zapolskiy , Wim Van Sebroeck , Sasha Levin Subject: [PATCH 5.10 125/243] watchdog: Fix possible use-after-free by calling del_timer_sync() Date: Mon, 19 Jul 2021 16:52:34 +0200 Message-Id: <20210719144944.942445469@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144940.904087935@linuxfoundation.org> References: <20210719144940.904087935@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zou Wei [ Upstream commit d0212f095ab56672f6f36aabc605bda205e1e0bf ] This driver's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself. Reported-by: Hulk Robot Signed-off-by: Zou Wei Reviewed-by: Guenter Roeck Acked-by: Vladimir Zapolskiy Link: https://lore.kernel.org/r/1620802676-19701-1-git-send-email-zou_wei@huawei.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck Signed-off-by: Sasha Levin --- drivers/watchdog/lpc18xx_wdt.c | 2 +- drivers/watchdog/w83877f_wdt.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/watchdog/lpc18xx_wdt.c b/drivers/watchdog/lpc18xx_wdt.c index 78cf11c94941..60b6d74f267d 100644 --- a/drivers/watchdog/lpc18xx_wdt.c +++ b/drivers/watchdog/lpc18xx_wdt.c @@ -292,7 +292,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev) struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev); dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n"); - del_timer(&lpc18xx_wdt->timer); + del_timer_sync(&lpc18xx_wdt->timer); return 0; } diff --git a/drivers/watchdog/w83877f_wdt.c b/drivers/watchdog/w83877f_wdt.c index 5772cc5d3780..f2650863fd02 100644 --- a/drivers/watchdog/w83877f_wdt.c +++ b/drivers/watchdog/w83877f_wdt.c @@ -166,7 +166,7 @@ static void wdt_startup(void) static void wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); wdt_change(WDT_DISABLE); -- 2.30.2